.\"	$OpenBSD: umount.8,v 1.16 2007/05/31 19:19:48 jmc Exp $
.\"	$NetBSD: umount.8,v 1.2 1995/03/18 15:01:35 cgd Exp $
.\"
.\" Copyright (c) 1980, 1989, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)umount.8	8.1 (Berkeley) 2/20/94
.\"
.Dd $Mdocdate: May 31 2007 $
.Dt UMOUNT 8
.Os
.Sh NAME
.Nm umount
.Nd unmount file systems
.Sh SYNOPSIS
.Nm umount
.Op Fl fv
.Ar special | node
.Nm umount
.Fl a
.Op Fl fv
.Op Fl h Ar host
.Op Fl t Ar type
.Sh DESCRIPTION
The
.Nm
command
calls the
.Xr unmount 2
system call to remove a
.Ar special
device or
.Ar node
.Pf ( Bo Ar rhost :
.Bc Ar path )
from the file system tree.
Multiple devices and nodes may be specified on the command line.
If neither
.Ar special
nor
.Ar node
are provided, the appropriate information is taken from the kernel.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl a
All of the file systems except root returned by
.Xr getmntinfo 3
are unmounted.
.It Fl f
The file system is forcibly unmounted.
Active special devices continue to work,
but all other files return errors if further accesses are attempted.
The root file system cannot be forcibly unmounted.
.It Fl h Ar host
Only filesystems mounted from the specified host will be
unmounted.
This option implies the
.Fl a
option and, unless otherwise specified with the
.Fl t
option, will only unmount NFS filesystems.
.It Fl t Ar type
Indicates that actions should only be taken on
filesystems of the specified type.
More than one type may be specified in a comma separated list.
The list of filesystem types can be prefixed with
.Dq no
to specify the filesystem types for which action should
.Em not
be taken.
For example, the following command
unmounts all filesystems of type
NFS and MFS:
.Bd -literal -offset indent
# umount -a -t nfs,mfs
.Ed
.It Fl v
Verbose, additional information is printed out as each file system
is unmounted.
.El
.Sh SEE ALSO
.Xr unmount 2 ,
.Xr getmntinfo 3 ,
.Xr mount 8
.Sh HISTORY
A
.Nm
command appeared in
.At v3 .
